      1   1 Identifier a
      1   2 Op_assign
      1   3 Integer 11 
      1   5 Semicolon
      2   1 Identifier b
      2   2 Op_assign
      2   3 Integer 22 
      2   5 Semicolon
      3   1 Identifier c
      3   2 Op_assign
      3   3 Integer 33 
      3   5 Semicolon
      4   1 End_of_input
